The invention relates to an apparatus and method for clamping printing plates on a plate cylinder. In addition, the invention relates to a plate cylinder.
Printing couples of printing presses, such as web-fed printing presses, for example, have a plate cylinder, a transfer cylinder, an inking couple as well as preferably a moistening unit. Printing plates are normally arranged on the plate cylinder, which is the reason why the plate cylinder is also called an engraving cylinder. Rubber offset blankets are normally positioned on the transfer cylinders, which is why the transfer cylinders are also designated as blanket cylinders.
Clamping mechanisms that are integrated into a lockup slot of the plate cylinder are used to arrange or clamp printing plates on the circumference of the plate cylinder. Such a clamping mechanism can be used to clamp a leading end and/or a trailing end of at least one to-be-clamped printing plate in the lockup slot.
Clamping mechanisms known from practice have a clamping element as well as an actuating element, whereby both the clamping element as well as the actuating element are integrated into a lockup slot of a plate cylinder. The actuating element can be used to transfer the clamping element between two positions, namely between a first position, in which the clamping element clamps the leading end and/or the trailing end of the or each printing plate, and a second position, in which the clamping element releases the leading end and/or the trailing end of the or each printing plate.
The disadvantage of clamping mechanisms for printing plates known from practice is that the clamping mechanisms can have a relatively complex structure.
Starting herefrom, the present invention is based on the objective of creating a novel clamping mechanism for printing plates having a simple structure and a plate cylinder with such a clamping mechanism.
According to the invention, the clamping element can be adjusted exclusively in the radial direction of the plate cylinder and the actuating element exclusively in the axial direction of the plate cylinder in such a way that, depending upon the relative axial position of the actuating element with respect to the clamping element, the clamping element can be displaced either radially outwardly due to a spring force of at least one clamping spring for clamping the leading end and/or the trailing end of the or each printing plate or can be displaced radially inwardly against the spring force of the or each clamping spring for releasing the leading end and/or the trailing end of the or each printing plate.
The inventive clamping mechanism for printing plates has a relatively simple structure. Thus, the inventive clamping mechanism has a clamping element, which can be adjusted exclusively in the radial direction of the plate cylinder, and an actuating element, which can be adjusted exclusively in the axial direction of the plate cylinder. Depending on the relative axial position of the actuating element with respect to the clamping element, the clamping element can either clamp or release the leading end and/or the trailing end of the or each printing plate in the lockup slot. To do so, the clamping element cooperates with at least one clamping spring.
Preferred developments of the invention are yielded from the following description. Without being limited hereto, exemplary embodiments of the invention are explained in greater detail on the basis of the drawings.